Underwater diving equipment typically includes an air supply tank, a buoyancy compensator and an air supply system for delivering air from the air supply tank to the diver and the buoyancy compensator. Conventional air supply systems include a first stage regulator, a second stage regulator and a power inflator. As conventionally known, the first stage regulator delivers air to the second stage regulator through a first high-pressure line and delivers air to the power inflator through a second high-pressure line. The second stage regulator delivers air to the diver in response to inhalation by the diver.
The power inflator comprises a valve mechanism that enables the diver to inflate the buoyancy compensator by selectively directing air from the second high-pressure line to the buoyancy compensator via a large diameter flexible hose fitted to the buoyancy compensator. Power inflators frequently additionally include an exhaust valve mechanism and a mouth piece for enabling air to be exhausted from the buoyancy compensator through the large diameter hose and for enabling the diver to orally inflate the buoyancy compensator through the mouth piece and through the large diameter hose.
In many diving situations, it is desirable that the air supply system additionally include an auxiliary second stage regulator should the primary second stage regulator of the diver or a companion diver fail or otherwise becomes inoperable. In "octopus" air supply systems, the auxiliary second stage regulator is connected to the first stage regulator by yet a third high-pressure line extending from the first stage regulator. As a result, octopus air supply systems generally include three high-pressure lines extending from the first stage regulator for providing air to the power inflator, the primary second stage regulator and the auxiliary second stage regulator. Consequently, octopus air supply systems are complex, difficult to manufacture and difficult to use and manipulate underwater.
To eliminate one of the high-pressure lines extending from the first stage regulator and thereby simplify the construction and manipulation of the system under water, other air supply systems include a Y-shaped splitter tube having an inlet and two outlets for supplying air from a single high-pressure line to the power inflator connected to one outlet and to the auxiliary second stage regulator connected at the other outlet. Although effective at eliminating one of the high-pressure lines extending from the first stage regulator, these air supply systems still require two separate and independent units, the power inflator and the auxiliary second stage regulator. Consequently, this system is bulky and requires the diver to shift back and forth between the mouth piece of the auxiliary second stage regulator and the power inflator if the diver needs to orally inflate the buoyancy compensator while utilizing the auxiliary second stage regulator. Shifting between mouth pieces requires that water, sand and other particles within the mouth pieces be purged before use and requires valuable time.
To eliminate the need for a third high-pressure line and to also eliminate the need to shift between the mouth pieces of the auxiliary second stage regulator and the power inflator, a third air supply system utilizing an integrated power inflator and regulator has been developed. This integrated inflator-second stage regulator, described in U.S. Pat. No. 4,227,521, and assigned to UnderSea Industries, Inc., a division of Johnson Worldwide Associates, utilizes a single integrated mechanism connected to a single high-pressure line and provides the same functions previously provided by the separate power inflator and the separate auxiliary second stage regulator. Consequently, this air supply system is less complex and more easy to operate under water. However, because this system utilizes a single integrated mechanism for providing the functions of both the power inflator and the auxiliary second stage regulator, both functions must be inherently purchased together in contrast to the two outlet system in which the power inflator and the auxiliary second stage regulator can be purchased separately at different times by the diver to enable the diver to upgrade his or her air supply system according to the diver's individual needs and budget.
As a result, there is a continuing need for an air supply system that requires a minimum number of high-pressure lines extending from the first stage regulator, that eliminates the necessity of shifting between separate mouth pieces of an auxiliary second stage regulator and a power inflator and enables the diver to individually upgrade his or her air supply system based upon the diver's needs and budget.